Unconventional shale gas production is often characterized by a short period of high production followed by a rapid decline in the production rate. Given the high costs of hydraulic fracturing and horizontal drilling, it is critical to identify the mechanisms behind the production loss. The existing shale gas production models often assume constant matrix permeability. However, laboratory obser...

The progressive collapse behavior and energy release of columnar jointed basalts (CJBs) can be greatly influenced by different joint distance ratios. By adopting the digital image correlation, a series heterogeneous CJB models are established. continuous fracture process acoustic emissions (AEs) captured numerically under varying lateral pressures. load curves ratios model boundaries analyzed. ...

Gas hydrates (GH) are well known to have an influential effect on the velocity and attenuation of gas hydrate-bearing sediments (GHBS). Based rock physics modeling, sediment has been extensively used characterize distribution hydrate. However, results obtained from different models show a significant variation. In this study, we firstly review compare existing modeling for attenuation. The assu...

A method is devised for estimating the potential permeability of fracture networks from attributes of fractures observed in outcrop. The technique, which is intended as a complement to traditional approaches, is based on type curves that represent various combinations of fracture lengths, fracture orientations and proportions (i.e., intensities) of fractures that participate in flow. Numerical ...

Present study deals with the prediction of crack initiation angle for mixed mode (I/II) fracture using finite element techniques and J-Integral based approach. The FE code ANSYS is used to estimate the stress intensity factor numerically. The estimated values of SIF were incorporated into six different crack initiation angle criteria to predict the crack initiation angle. Single edge crack spec...

Reactive fluid-flow experiments in fractures subjected to normal stress suggest the potential for either increased or decreased permeability resulting from fracture-surface dissolution. We present a computational model that couples mechanical deformation and chemical alteration of fractures subjected to constant normal stress and reactive fluid flow. The model explicitly represents micro-scale ...

[1] Results are reported for water flow-through experiments conducted on an artificial fracture in limestone at room temperature and under ambient confining stress of 3.5 MPa. Tests are concurrently monitored for mineral mass loss or gain and for changes in differential pressure between the inlet and outlet, throughout the 1500-hour duration of the experiment. Periodic imaging by X-ray computed...

We present the results of compositional reservoir simulation of a prototypical CO2 sequestration project in a deep saline aquifer. The objective was to better understand and quantify estimates of the most important CO2 storage mechanisms under realistic physical conditions. Simulations of a few decades of CO2 injection followed by 10 to 10 years of natural gradient flow were done. The impact of...

Control of the grouting pressure within critical for crack propagation in Ordovician limestone can not only ensure grout penetration length, but also prevent risk creating an artificial water channel. Based on fracture mechanics theory, a formula was proposed to calculate mixed mode I-II cracks limestone. The necessary conditions tilted opening, rationality existing empirical value maximum allo...

[1] Joint sets within sedimentary basins are commonly interpreted to have formed by tensile failure in conditions where pore fluid pressure was elevated. Such tensile fractures are inferred to be a part of the process that relieves high fluid pressure by locally increasing rock permeability. In spite of the importance of this feedback mechanism, the detailed mechanics of hydraulic fracture gene...